Never understood the bullet sizing thing...

[CarolinaGuy]

Tried wiki first, still not getting it.

I would think that say, as far as handguns go anyway, that the calibers would go up in increasing size.

.357
.38
.44
.45
.50

etc

However, I went and fired my 357 for the first time yesterday, and that put a little sting on using 357 mags.

Now my 9mm and 38 (fired from the 357) were just a little twitch coming from the gun. So why, at least to the 38, is a smaller number [357] 100 times the oomphhh?

Again, like in Dirty Harry. He tells Mr Badguy that the 44magnum is the most powerful handgun in the world. But a .45 and .50 are both "bigger". So what gives. What exactly do those numbers mean, and why would a little number have infinite recoil over a bigger number?

And yes, I'm a 3 month firearm newb...

[tdyoung58]

You have to figure in the powder charge behind the bullet, lenght of barrel and all that affect the 'power' of a shot

a .45 acp has less of a powder charge than a .44 mag but yet a .223 has more 'power' than both due to the powder charge behind the bullet even though it's less than half the size of either.

Powder = Power, not bullet size

[rwilson452]

lets confuse things a bit. th e.357 and 39spl both fire the same diameter bullet. the difference is the 357 case is bigger and holds more powder. guns designed for the 357 can handle more pressure. the 38 spl need to be safe in any gun chambered for it. this includes pistols made a century ago. as others have said it more about how hard your pushing the bullet and the weight of the bullet than it is the bullet diameter.

Tried wiki first, still not getting it.

I would think that say, as far as handguns go anyway, that the calibers would go up in increasing size.

.357
.38
.44
.45
.50

etc

However, I went and fired my 357 for the first time yesterday, and that put a little sting on using 357 mags.

Now my 9mm and 38 (fired from the 357) were just a little twitch coming from the gun. So why, at least to the 38, is a smaller number [357] 100 times the oomphhh?

Again, like in Dirty Harry. He tells Mr Badguy that the 44magnum is the most powerful handgun in the world. But a .45 and .50 are both "bigger". So what gives. What exactly do those numbers mean, and why would a little number have infinite recoil over a bigger number?

And yes, I'm a 3 month firearm newb...

[ChamberedRound]

The number refers to the diameter of the bullet, or caliber. The one exception to this is the .38 special; the .38 special uses a .357 bullet, and .38 is the approximate diameter of the loaded case. Excepting the .38 special, larger number, larger bullet.

Now I'm not a cartridge loading expert, but bullet size alone isn't the sole factor in the "oomph", power, or force of the bullet when fired. That has to do with bullet weight (which in part IS related to size), and the loading of the cartridge.

For example, .357 Magnum is typically loaded much hotter (more gunpowder) than the .38, despite both being the same bullet size (.357 in). The .357 cartridge casings are designed to handle the higher pressures associated with burning more powder. Higher pressures mean more energy, and compared to the .38 this extra energy can be used to fire:

- A heaver bullet at approximately the same speed, or
- A bullet approximately the same weight at faster speed, or
- Something in between

The next time you're buying ammunition for your gun, take a look at the box or the manufacturer's website. Usually, basic information about the weight of the bullet (in grains), and the velocity of the bullet at the muzzle (in ft/sec) is provided. There's way more information that can be obtained about specific caliber cartridges, (number of grains of powder they're loaded with, Power Factor, ballistics testing data, etc.), and the loading combinations are not only endless but vary by manufacturer. If you're so inclined, I'd encourage you to do some more research on the topic, as there's a LOT of information out there. Also, take a look at our "Ammunition and Reloading" forum here on the site; you might be able to get some questions answered by local people who do this stuff all the time.

Have fun!

[mjfletcher]

Seems everyone already got you the information, but i'll toss in my .02 worth anyway. As has been said, caliber is just a measurement of the diameter of the bullet, either in 100ths of an inch (.38, .357, .40) or mm's (9mm, 7.62mm). Bullet weight, powder charge, and muzzle length will all play into the felt recoil.

Quick physics 101: With an identical powder charge, the more energy that is transfered from the expanding gas inside the chamber/barrel to the bullet (and the frame of the gun), the less felt recoil there will be (and the greater the bullets velocity will be)

ie:
A lighter bullet will absorb more of the energy than from the expanding gas than a heavier bullet in the same length barrel so the lighter bullet will have less felt recoil.
A longer barrel allows for more energy to be absorbed because the bullet is in the barrel for a longer time (fractions of a second, but in physics that can be a long time) so there will be less felt recoil from the same weight bullet fired from a 5 inch barrel than from a 3 inch barrel.
An all steel gun, having more mass than a steel/polymer gun will absorb more of the energy not absorbed by the bullet resulting in less felt recoil in an all steel gun with the identical bullet, powder charge, and barrel length of a steel/polymer gun.

A larger powder charge will, of course, result in more felt recoil.

[jofreder]

Now my 9mm and 38 (fired from the 357) were just a little twitch coming from the gun. So why, at least to the 38, is a smaller number [357] 100 times the oomphhh?

Does this mean you are shooting 9mm luger in your .357?

[Dave in PA]

And to further confuse the issue, there are different gunpowders used for different things. Some powders burn slower than others. Most pistol cartridges use a 'fast' powder while most rifle cartridges use a 'slow' powder.

[djturnz]

Does this mean you are shooting 9mm luger in your .357?

Wondering the same thing.

[Statkowski]

Just to keep things muddy, compare a 5.56-mm round with a .223-cal. round - both are the same size. The 5.56-mm is the military round and has more oomph. A rifle designed for .223-cal. (the civilian round) can't handle the 5.56 ammo - less pressure or something like that.

[djturnz]

I may be wrong but I am pretty sure that it's not a pressure thing between .223 and 5.56nato. It's chamber tolerance. a Rifle chambered in 556 can chamber both but a semi chambered in 223 may not be able to chamber a 556.

I heard it explained on the radio the other day but I don't remember the exacts.

News and Press Releases
.223 Rem VS 5.56mm Paul Nowak5/4/2001.223 Rem VS 5.56mm

There are a lot of questions about these two cartridges. Many people think they are identical - merely different designations for commercial and military. The truth is that, although somewhat similar, they are not the same and you should know the differences before buying either cartridge.


The cartridge casings for both calibers have basically the same length and exterior dimensions.
The 5.56 round, loaded to Military Specification, typically has higher velocity and chamber pressure than the .223 Rem.
The 5.56 cartridge case may have thicker walls, and a thicker head, for extra strength. This better contains the higher chamber pressure. However, a thicker case reduces powder capacity, which is of concern to the reloader.
The 5.56mm and .223 Rem chambers are nearly identical. The difference is in the "Leade". Leade is defined as the portion of the barrel directly in front of the chamber where the rifling has been conically removed to allow room for the seated bullet. It is also more commonly known as the throat. Leade in a .223 Rem chamber is usually .085". In a 5.56mm chamber the leade is typically .162", or almost twice as much as in the 223 Rem chamber.
You can fire .223 Rem cartridges in 5.56mm chambers with this longer leade, but you will generally have a slight loss in accuracy and velocity over firing the .223 round in the chamber with the shorter leade it was designed for.
Problems may occur when firing the higher-pressure 5.56mm cartridge in a .223 chamber with its much shorter leade. It is generally known that shortening the leade can dramatically increase chamber pressure. In some cases, this higher pressure could result in primer pocket gas leaks, blown cartridge case heads and gun functioning issues.
The 5.56mm military cartridge fired in a .223 Rem chamber is considered by SAAMI (Small Arm and Ammunition Manufacturers Institute) to be an unsafe ammunition combination.

Before buying either of these two types of ammunition, always check your gun to find what caliber it is chambered for, then buy the appropriate ammunition. Most 5.56mm rounds made have full metal jacket bullets. Performance bullets - soft points, hollow points, Ballistic Silvertips, etc. - are loaded in .223 Rem cartridges. Firing a .223 Rem cartridge in a 5.56mm-chambered gun is safe and merely gives you slightly reduced velocity and accuracy. However we do not recommend, nor does SAAMI recommend, firing a 5.56mm cartridge in a gun chambered for the .223 Rem as the shorter leade can cause pressure-related problems.

After reading this, pressure is involved, but it's the "LEADE" of the chamber that is the difference.